I think this could probably push DCCC chair Chris Van Hollen into the Obama camp. Obama also carried his Maryland district handily. I would also look for some other freshmen Dems like possibly Harry Mitchell and Jerry McNerney who are in tough races to go to Obama.
Harry Mitchell has the tough proposition of being in Arizona this cycle all by itself. McNerney, though... very good chance.
Mitchell will face a tough reelection battles, but he's not in imminent danger of defeat. Never forget that Mitchell is a demigod in Tempe; after he retired as mayor, the city built a statue in his honor.
The GOP field against Mitchell is also quite diffuse and weak, IIRC.